Hysteretic devices



April 4, 1961 M. w. GREEN HYSTERETIC DEVICES 5 Sheets-Sheet 1 FiledMarch 20, 1957 HVPTVTOR. MILTUN 1N. [.REEN

M. w. GREEN 2,978,682 HYSTERETIC DEVICES 5 Sheets-Sheet 2 April-4, 1961Filed March 2o, 1957 MHLTUN 1N. EREEN BY TTOJVET April 4, 1961 M.,w.GREEN HYSTERETIC DEVICES 5 Sheets-Sheet 5 Filed March 20, 1957 T TammyApril 4, 1961 M. w. GREEN HYSTERETIC DEVICES 5 Sheets-Sheet 4 FiledMarch 20, 1957 April 4, 1961 M. w. GREEN HYSTERETIC DEVICES 5Sheets-Sheet 5 Filed March 20, 1957 INVENTOR. MILTUN IN. GREEN BY TTRVfYUnite HYSTERETIC DEVICES Filed Mar. 20, 1957, Ser. No. 647,256 14Claims. (Cl. 340-174) lThis invention relates to information handlingsystems which make use of both magnetic and ferroelectric elements, andmore particularly to systems useful as shift registers in which storedsignals are successively shifted under the control of shifting signals,and to scaling circuits and counting circuits which are used to providean output signal after a given number of shifting signals, and the like.

It is an object of the present invention to provide systems of the typeset forth in which use is made of the ferroelectric elements in a novelmanner.

Anothe-r lobject of the present invention is to provide improved systemsof the type set forth, wherein the ferroelectric elements are used in amanner to prevent undesired interactions.

Still another object of the present invention is to provide improvedsystems as above set forth which make use of ferroelectric elements in anovel manner and which can be operated in either forward or reversedirections in accordance with the polarity of the shifting signals.

According to the present invention, a plurality o-f cores of magneticmaterial having rectangular hysteresis loop characteristics aresuccessively interconnected by transfer loops. Each transfer loopincludes a condenser of ferroelectric material also having a rectangularhysteresis loop characteristic. First and second shift lines are linkedto alternate ones of the cores. A signal stored in one of the cores issuccessively transferred through the ferroelectric condensers tosuccessively higher order cores byalternately applying shifting signalsto the shift windings. The ferroelectric condensers operate to preventcurrent ow in the transfer loops except when a signal Yis beingtransferred between desired ones of the cores.

In the accompanying drawing:

Fig. 1 is a schematic diagram of a device according to the invention,using magnetic cores and ferroelectric condensers; l

Fig. 2 is a graph of the hysteresis characteristic for a suitablerectangular hysteresis loop magnetic material useful in explaining theoperation of the device of Fig. 1;

Fig. 3 is a graph of the hysteresis characteristic for a suitablerectangular hysteresis loo-p ferroelectric condenser useful inexplaining the operation of the device of Fig. l;

Fig. 4 is a schematic diagram of a device according to the invention,illustrating various ways of coupling load devices to the elements;

Fig. S is a schematic diagram of a device according to aten-t thepresent invention, having means for setting the ferroelectric cells todesired states;

Fig. 6 is a schematic diagram of a device according to the invention,having means for resetting the ferroelectric condensers, and

Fig. 7 is a schematic diagram ,of another embodiment lof a deviceaccording to the invention, using an`auxiliary magnetic core in eachtransfer loop. f A

In Fig. 1, a system according to the invention .illusratively Vhas fourseparate stages. More or less than four stages may be used, if desired.Each st-age includes .a

2 separate one of the magnetic cores 10a, 10b, 10c and 10d. The cores 10each are made from magnetic material having appreciable remanence, andeach may be of rectangular hysteresis loop magnetic material. Certainceramicmaterial such as manganese-magnesium ferrite, andl certainmetallic materials such as molybdenum- Permalloy, exhibit the desiredlcharacteristics. Each core 1f; is provided with ank input winding 12 andan output winding 14. For. convenience of drawing, the windings areshownvas single-turnwindings. It is understood, however, that multiturnwindings may be used. One shift line 16 links the cores 10of theodd-numbered stages, and another shift line 18 -links the cores 10 ofthe even-numbered stages. First and second sources 17 and 19 of shiftsignals are connected respectively to the lirst and second shift lines16 and 18. The shift lines 16 and 1S, after linking the cores 10, areconnected to a source of reference potential, indicated in the drawingby the conventional ground symbol. f The shift sources 17 and 19 alsoare connected to ground. The conventional transformer notation is usedto-indicate the sense of linkage of the windings to the cores.

Three transfer loops 20, 21 and 22 connect the cores 10 in cascadebyconnecting the output winding 14 of one `core 10 to the input winding12 of a succeeding core 10. Each of the transfer loops 20, 21 and 22includes a separate one of the ferroelectric condensers 24, 25 and 26having respectively the pairs of terminals 24a, b, 25a, b and 26a, b.Any one of the condensers is connected in any one of the transfer loopsin series with the output and input windings 14 and 12 of that transferloop. The a electrode vof a condenser is connected to the markedterminal of a transfer loop output winding 14, and the b electrode `ofany condenser is connected to the unmarked terminal of the transfer loopinput .winding 12. Each of the condensers has two states o-f appreciableremanence, and may have a dielectric of substantially rectangularhysteresis loop material. Certain materials, such as barium-titanate,exhibit the desired characteristics.'

A first input device 27 or a second output device 28 may -be selectivelyconnected across the terminals of the input winding 12a of the lowestorder core 10a by means of a first double-pole, double-throw reversingswitch 36. The terminals of the input winding 12d are' connected to themovable armof the rst reversing switch 3U. The output terminals orf-theliirst input device 27 are connected to one pair of tixed terminals 31of the reversing switch 3tlg and the input terminals of the secondoutput device 28 are connected to the other pair of fixed terminals 32of the reversing switch 30. By means of a second, double-pole,double-throw reversing switch 3S, selectively, the output `from theVhighest order core 10d may be applied to la first output lo-ad device33, or input signals may be applied to the output winding 14d from asecond input device 34. The output winding 14d of the core 10d isconnected ,to themovable arm of the second reversing switch 35. Theiirst;output device33 is connected to one pair 36 of fixed terminals ofthe second reversing switch 35; and the terminal 38 of the secondreversing switch 35. The other i Acenter terminal 39 of the secondreversing switch35 is connected to the unmarked terminal of the voutputwind- `ing 14a'.v Any suitablev electronic switchingmeans can l be usedfor the reversing switches 30 and 35.

A hysteresis curve 40 for core 10 of Figli has two vremanent states,arbitrarily a magnetic material suitable forusein the Asystem of-Fig. 1vis shown in Fig. 2. VA

agresse core 10. Relatively little liux change is produced in a corewhen it is driven from remanence to saturation along a horizontalportion of the hysteresis curve 32. A positive magnetizing force H,greater than a coercive force Hc changes the magnetization of the corefrom the state N to the state P. Similarly, a negative magnetizing forcegreater in amplitude than a coercive force -Hc changes a core from thestate P to the state N.

A hysteresis curve 42 plotting charge (Q) against applied voltage (V)for a capacitorh'aving a ferroelectric material dielectric and suitablefor use in the system of Fig. l is shown in Fig. 3. A condenser having adielectric of ferroelectric material also has two remanent states,arbitrarily designated as positive P' and negative N' in which theremanent charge is. an appreciable portion of the saturated charge. Oneremanent state P' corresponds to a charge in one direction, say whichthe electrode a being positive relative tothe'electrode b of acondenser; and the other remanent state N' corresponds to a charge inthe opposite direction with the electrode b being positive relative .tothe electrode a of a condenser.

`Relatively little change of charge is produced in a condenser when itis driven by a voltage from remanence to saturation along a horizontalportion of the hysteresis curve 42. An applied voltage of one polarity,for example a voltage making the condenser electrode a posil tiverelative to the condenser electrode b, greater than a coercive voltageVc changes a condenser from the state N t0 the state Pf. An appliedvoltage of opposite polarity, making the condenser electrode b positiverelative to the condenser electrode a, greater in amplitude than acoercive voltage -Vc changes a condenser from the state P' to the stateN'. f

Referring now to Fig. l, assume that it is desired to shift signalsinthe forward, or left-to-right, direction from the first input device27 to the first output device 33. The first input device 27 is coupledto the first stage core 10a by thro-Wing the movable arm of the firstreversing switch 30 to the left (asviewed in the drawing), and the firstoutput device 33is coupled'to the-last stage core 10d by`throwing themovable arm of. the second reversing switch :3S to the right, as viewedin the drawing. Assume also that all the cores 10 aremagnetized in thesame one state, vsay the state P, and that allfthe condensers arepolarized in the santel state, say the state N.

lf, now, a positive shift pulse 41 is applied to the odd shift line 16,the cores10a and 10c are each driven from remanence in the state P tosaturation in the same state p P. Accordingly, a relatively small flux`change is produced in eachA of the cores 10a and 10c. These relabeopen-circuited when the shift signals are applied or, if desired, aseparate condenser (not shown) may be connected between the first inputdevice 27 and the core 10a input winding 12a. The relatively smallvoltage induced in the input winding 12C of the core 10c by the positiveshift pulse 41 also is in a direction to change the condenser 25 of thetransfer loop 21 from the initial state N' to the other state P'.However, this small induced voltage also is less than the coercivevoltage Vc of the condenser 25. Therefore, substantially no change ofcharge is produced in the condenser 25. After the shift pulse 41terminates, the condenser 25 returns to, or very near, its initialremanent condition in the state N'.

When a positive shift pulse 43 is applied to the even shift line 18, thecores 10b and 10d are driven from remanence in the initial state P tosaturation in the state P. The relatively small ux changes produced inthe cores 10b and 10d likewise do not produce any significant change inthe initial remanent conditions of the condensers 24, 25 and 26 of thecoupled transfer loops 20, 21 and 22. No significant changes of chargeare produced in the condensers 24, 25 and 26 for the same reasons thatthe small flux changes in the cores 16a and 10c do not produce changesof charge in these condensers. The system of Fig. l responds in similarfashion to repeated applications of odd and even shift pulses 41 and 43.The above-described condition of the system corresponds to a resetcondition where each core 10 and each condenser remains in its initialremanentstate.

Assume, now, that a positive input pulse 44 is applied by the iirstinput device 26 to the input winding 12a of the first stage core 10a.AThe positive input pulse 44 is in a direction to make the unmarkedterminal of the input winding 12 positive relative to the markedterminal. The positive input pulse 44 changes the core 10a from theinitial state P to the state N. The relatively large flux changeproduced in the core 10a is in a direction to make the marked terminalof the output winding 14a negative relative to its unmarked terminal.Accordingly, the condenser 24 of the transfer loop 20 is driven fromremanence in the state N to saturationin the state N', and relativelylittle current ows in the transfer loop 20. Relatively little currentlio-Ws in the transfer loop 20 because the point representing the stateof the condenser 24 moves from remanence to saturation along the bottomhorizontal portion of the curve 42 of Fig. 2. Accordingly, relativelylittle change of charge is produced in the ,l condenser 24. Therefore,only a relatively small current,

tively small flux changes each induces a relatively small voltage acrossthe input windings 12a and 12e andthe output windings 14a and 14e inadirecton to make their marked terminals positive relative to' theirunmarked terminals. The small, positive voltages at the marked terminalsofthe output windings 14aand 14e of Vthe cores 10a and 10c are appliedbetweenV 'the electrodes of the condensers 24 and 26 of the transfer'loops 20 and 22, respectively. The positive voltages at the electrodes24a and 26a are each in a direction'to change the condensers 24 and 26from their initial state N'A totheir other states P'. However, thesesmall, positive voltages areY each less than the coercive voltageVc Tofthe `condensers-z24 and 26. Accordingly, relatively little change ofchargeis produced in the condensers 24 and .26 and, upon` termiditionslinv the initial state; N' i; The'finput devicet27-may proportional tothe change of charge in the condenser 24, can flow in the transfer loop20. This relatively small current produces insufficient magnetizingforce to significantly change the initial remanent condition of thesecond-stage core 10b. A voltage also is induced in the odd shift line16 when the core 10a is changed from the state P to the state N.However, the first shift current source 17 is open-circuited at thistime.

Now, when a positive shift pulse 41 is applied to the i odd shift line16, the iirst-stage core 10a is changed from the state N to the state P.A relatively large flux change is produced in the core 10a, and arelatively large voltage is induced across its outputvwinding 14a in adirection to make its marked terminal positive relative to its unmarkedterminal. This large induced voltage changes thek condenser 24 of thetransfer loop 20 from theinitial state N' to the other state P', therebyinducingra relatively large transfer current in the transfer; loop 20.The relatively large transfer current flows into the input winding 12bat its unmarked terminal, and changes thecore 10b from the initial stateP to the other state 'N-.Y The relatively 'large flux change in the core10b induces a voltage in its output winding 14h in a direction to makeits Amarked terminal negative relative to the unmarked terminal.However, substantially no current flows in tial remanent states P andinitial state N'. The ux change produced in the second- Vstage core balso induces a voltage in the even shift line 18. However, no currentows in the even shift line 18 because the even shift current source 19is open-circuited at this time.

Accordingly, after termination of the odd shift pulse 41, the iirststage core 10a is in its initial state P, the condenser 24 of thetransfer loopis in its other state P', and the second-stage core 10b isin the other state N. Each of the other cores 10 and the condensers arein their initial remanent states.

When an even shift pulse 43 is next applied to the even shift line 18,the second-stage core 10b is changed from the state N to the state P. Avoltage is induced in the output winding 14b of the core 10b, making itsmarked terminal positive relative to its unmarkedy terminal. Thisrelatively large voltage changes the condenser 25 of the transfer loop21 from the initial state N to the other state P. The resulting transfercurrent owing in the transfer loop 21 changes the third-stage core 10cfrom its initial state P to the other state N. No significant currentflow is produced in the third transfer loop 22, when the third-stagecore 10b is changed from the state N to the state P, because thecondenser 26 of the third transfer loop 22 is driven from remanence inthe state N to saturation in the same state N. Likewise, substantiallyno transfer current flows in the iirst transfer loop 20, when thesecond-stage core 10b is changed from the state P to the state N,because the voltage induced across its input winding 12b is in adirection to drive the condenser 24 of the first transfer loop` 20 fromremanence in the state P to saturation in the state P'. Also, no currentis produced in the odd shift line 16, when the third-stage core 10c ischanged from the initial state P to the other state N, because the firstshift current 'source 17 is open-circuited at this time.

Accordingly, after the even shift pulse 43 is terminated,

Vthe second-stage core 10b is in the initial state P, the

condensers 24 and 25 are each in the other state P', and the third-stagecore 10c is in the state N'. Each of the other cores and the remainingcondensers are in their ini- N, respectively.

Alternate application of odd and even shift pulses 41 and 43 transfersthe input signal successively from the third-stage core 10c to thefourth-stage core 10d, and from the fourth-stage'core 10d to the firstoutput device 33, in similar manner.

After the input signal initially received from the first input device 27is transferred to the output device 33, all of the condensers arepolarized in their other remanent states P' and all the cores 10 aremagnetized in their initial remanent states P. Accordingly, beforeanother signal is transferred from the first input device 27 to theiirst output device 33, each of the condensers is changed fromthe otherstate P to the reset statefN. Suitable means for restoring thecondensers to their reset states are described hereinafter. Y

ln shifting the input signalfrom one co-re to a succeediug core,theoutput voltage produced in the output winding of the transferringcore must be greater than the coercive voltage of the coupled?condenser. This core output voltage .depends upon the number of turns ofthe output winding and on the amplitude and rise time of s theshift-pulse appliedto the-shift line. Also,.for `a given number of turnsof an input winding, the transfer current able amount of transfercurrent by makingthe voltage applied to its electrodes suflicientlylarge. yAfter all the ux change is carried out in the receiving core inchanging from remanence in its initial state to saturation in its otherstate, substantially :all the voltage from the transferring core outputwinding appears across the` condenser. Accordingly, the condenser, if itis not already in its saturated state, is thereby completely switched toits saturated state. Therefore, the cores 10 and the condensers need notbe matched with each other and may be of different sizes. Thus, eachcore 10 and each condenser is completely changed from remianence tosaturation, provided the shift pulsescause voltage pulses of suicientlylarge amplitude and duration to be induced in the transfer loops. Y ,y

The first and second shift sources l17 and 19 preferably areconstant-current sources; Suitable, known constant'- current sourcesinclude other magnetic core circuits, pentode-type amplifier circuits,etc. Constant-current sources for driving a magnetic-core shiftingdevice are commercially available. n

Signals from the second-input device 34 can be shifted in the reverse,or right-to-left, direction to the second output device 28. In suchcase, the iirst and second reversing switches 30 and 35 are thrown tothe right and to the left, respectively. Each of the cores 10, however,is magnetized inthe state N. The cores 10 can be changed to their statesN by applying negative-polarity currents to the odd and even shift lines16 and 18. These applied currents may have relatively long rise times sothat the voltages induced across the input and the output windings 12and l14 of the cores 10 are of relatively small amplitude. Any suitablemeans, including the shift sources 17 and 19, lmay be used for changingthe cores 10 to their states N. Each of the condensers is polarized inthe state P by any suitable means, described hereinafter.Negative-polarity shift signals 45 and 47 are applied to the odd andeven shift lines 16 and 18, respectively.

In operation, when all the cores 10 are in the state N, a negative shiftpulse 45 from the first shift source 17 drives the cores 10a and 10cfrom remanence in the initial state N to saturation in the same state N.A relatively small flux change is produced in the cores 10a and 10b.These relatively small flux changes induce relatively small amplitudevoltages in the input and the output windings linked to the cores 10aand 10c in a direction to ymake their unmarked terminals positiverelative to' their marked terminals. Each of the condensers connected tothe windings receiving an induced voltage is driven from remanence inthe initial Ystate P towards the other state N'. However, the relativelysmall induced voltages do not exceed the coercive voltages ;'Vc `of thecondensers. Accordingly, after the negative shift pulse 45 isterminated, each of the cores and each of the condensers returns to itsinitial remanentstate.. Similarly, when a negative shift pulse ,47fisapplied'to the even shift line 18, the cores 10b and 10d :have a,relatively small viiux change produced therein.` .These relativelysmall flux changes also produce relatively small amplitude voltages inthe windings ,coupled tothe cores 10b. and 10d in a directionto drive.the

connectedv condensers from remanence in their inital state P' towardsthe-other, state N. After the negative .shift pulse 47' isterminated,however, each of the cores and produced in a transfer loop'mustbe ofsuflicient ampli- 4tude and duration tof produce a magnetizing forcegreater than'the coercive force of the receiving core. The amount -oftransfer current also depends, at leastv in part, upon the amplitude`and the yrise time ofthe shift pulse. Proportionally larger transfercurrents can be produced in the transfer loop coupling the transferringand the receiving :cores by making the voltage produced in theoutputwinding lof the ,transferring core proportionally larger. That" is, the'condenser 'of the transfer loop can'pass any suit# each of thecondensers is-substantially-in itsinitial remaf nent; state.Repeatedyapplication of negative odd and even, Shiftpulses45 Vand u47does not Vcauser any `ofthe' cores or any of the condensers to changeits initialremanent state. This condition of'thezsystem, therefore,'corresponds-to another reset condition wherein the cores-10 are` all inthe same state N and all the condensers are in `the same state P.

Assume, now,A that aipositive voltage pulse .49 is applied i by thevsecond input device -34 to the, output (.now input) -windingxmd of thefourti'hsta'ge core 10d throughtheficondenser 29. Thei voltage pulse; 49vchanges.. the condenser' terminal and changes the core d from itsinitial state N to its other state P. The relatively large flux changein the core 10d induces a voltage in its input (now output) 4winding 12din a direction to drive the condenser 26 from its initial state P' tosaturation in the same state P'. Accordingly, relatively little currentows in the transfer loop 22 between the cores 10d and 10c. After theinput signal 49 is terminated, the fourth-stage core 10d is in the otherstate P, and the condenser 29 is in itsother state N. Each ofthe othercores and condensers is in its initial remanent state N or P',respectively.

f The next, negative', even shift pulse 47 changes the core 10d from itsstateP to its initial state N. The relatively large flux change in thecore 10d induces a voltage across its input (now output) winding 12d ina direction, and of suiicient amplitude, to change the condenser 26 fromits initial state P' to the other kstate N'. The resulting current 'owin the transfer loop 22 flows into the winding 14c at its markedterminal and changes the core 10c from its initial state N to itsotherstate P. The relatively large li-ux change in the core 10c, in changingbetween the states N and P, does not produce any significant currentflow in the transfer loop 21 between the cores 10c and 10b. The fluxchange in the core 10d also induces a relatively large voltage in theoutput (now input) winding 14d of the core 10d. However, this inducedvoltage is in a direction to drive the condenser 29 further intosaturation in the state N in which it is already polarized. Therefore,relatively little current can ow in the winding 14d, the condenser 29,and the second input device 34. If desired, the second input device 34can be open-circuited after the input signal 49 is applied to the core10d.

Accordingly, after the negative, even shift signal 47 is terminated, thecore 10c is magnetized in the other state P, and the condensers 26 and29 :are each polarized in the other state N'. Each of the other coresand each of the other condensers is in its initial remanent state N andP', respectively.

The next, negative, odd shift pulse 45 shifts the input signal from thecore 10c to the core 10b in similar manner. The core I10c is returnedt'o its initial remanent state N, and the core 10b and the condenser 25are each changed to their other states P and N', respectively.

The next sequence of negative even and odd shift pulses 47 and 45 shiftsthe input signal from the core 10b to the core 10a, and from the core10a t'o the second output device 28. v

After the input signalreceived from the second input device 34 isshifted to the second output device 28, the cores 10 are all magnetizedin their initial remanent states N, and the condensers are all polarizedin their other remanent states N'.

The relatively large voltage induced Yin the input (now output) winding12a, when the'iirst-stage core 10a is changed from its initial state `Nto the other state P, is

applied to thefsecond output device 2S. 'Infcertain ap-v plications,this inducedrvoltage is not desired." For these applications,an'additional fen'oelectric condenser (not shown) may be connectedlbetween the core10a winding 12a and the'movable arrnof the reversingswitch 30 to block current flow from the input winding 12a when thecore"10a is changed vto the other'state P. Also', any suitable knownmeans can be used in the second output device 28 to disciiminate againstthe undesired voltageffrom thecore 10a. z i* The'system-.of Fig. "l canbe'zreturnedto its other reset condition by yreturning thecoresfll to'their statesP by applying positive current pulses to the `odd and evenshift in Fig. 4. The system of Fig. 4 is similar to the system of Fig.V1, and in Fig. 4 and the remaining iigures, like elements are designatedby like reference numerals.

A plurality of separate load devices 50a, 5,0b, 50c and 50d may belinked to respective ones of the cores 10 by linking additional` outputwindings 52a, 52b, 52e 'and 52d respectively` to the separate cores 10.Each of the loads is connected across a different one of these outputwindings. Eachitime a relatively large flux change is produced in 'acore, an output signal is induced across the output winding linked tothat core, and a signal is applied to its individually-connected load.VThe loads 50a to 50d maybe devices which are responsive to bothpolarity signals produced in the output windings 52a to 52d. Forexample, these devices may offer a resistive load, as indicated by thedotted resistive elements in each of the ,boxes representing the loads.If desired, however, an additionalV element, such as a ferroelectriccondenser, individual to each output winding 52a`to 52d, may beconnected in series with each of the output windings 52a to 52d. Theadditional ferroelectric element prevents an output signal of onepolarity in an output winding frornvproducing a signal in the connectedload.

Also,.if desired, separate loads 54a, S4b and 54C may be connectedindividually in each of the separate transfer loops'20, 21 and 22. v Aseparate load (not shown) may be connected in series with the condenser29 and the output winding14d of the core 10d. in place of the firstoutput device 33. Each timeta transfer current flows in one of thetransfer loops 20, 21 or 22, a signal is applied to the load device 54a,b, or c of that transfer loop. Preferably, theseA load devices oder Varesistive load to signals induced in the core output or input windings.When these separate load devices 52a, b, or c or 54a, b, or c arecoupled to the system elements, the amplitude and the rise time of theshift signals are adjusted to assure complete switching of the magneticcores 10 andthe condensers, despite the additional energy absorbed bythe load devices.

A reset circuit suitable for establishing all the condensers in aninitial remanent state N' or P' is shown in Fig. 5. Eachof the transferloops 20, 21 and 22 is connected to a common bus 56 to which resetsignals are applied by a source of potential, such as a battery 58. Athird, double-pole, double-throw reversing switch 60 is connectedbetween the battery 58 and the common bus'56., The batteryhSS isconnected in series with va current-limiting resistor 61 across thecenter terminals of the switch 60. The diagonally opposite 'fixedterminals 62 andV 63 of the reversing switch 60 are connected to thecommon bus 56. The other diagonally opposite fixed terminals64 and 65 ofthe reversing switch are connected to ground. The marked terminals ofthe input windings 12b,"12c and 12d of the transferloops 20, 21 and 22,respectively, are connected to the common bus 56. The. unmarkedterminals of the output windings 14a, b,v and vc are all connected toground. A singleLpole, single-throw-shorting switch `66 connectsthe-common bus56 to ground jatffthe fixedk terminal 63 of the thirdreversing switchj60. The shortinglswitch 66 is normally desired statefby usingasingle-throwiswitch -67. .The

` 35 is 4connectedftov ground. The lowerpair of contacts lines 16 and18. The condensers may be returned to their remanent states P' Yasdescribed hereinafter.

69aan`d 69b-of the single-throw switch'67 are connectedrespectively-tothe common bus 56 and the electrode 29b -ofthe condenser29.

The systems of-the present invention provide great'.

flexibility-inthe manner of connectingload devices: Ato the; magnetic.-core and '-.ferroelectric elements, as shown During theresetoperation,.the single-throw switch '67 is depressedA to connect thecondenser -.29 to the reset ldesired to. reset the condensers tothestate N', the re versing switch 60 is thrown to the left (as viewed inthe drawing) to connect -the positive terminal of the reset battery 58to the common bus 56. A positive voltage, therefore, is applied to eachof the condensers 24, 25, 26 and 29 in a direction to make their bterminals positive relative to their a terminals. This positive voltagechanges each of the condensers from the state P to the state N. Theresistance element 61 is used to limit the amount of current -that canow in any of the transfer loops when their connected condensers arebeing changed to the state N'. The value of the resistance element 61 ischosen so that the resultant current ilow is limited by the resistanceelement 61, rather than by the relatively small impedances of the coreswhich are driven further into saturation in their reset states P by thiscurrent. After the condensers are reset to their N' states, thereversing switch 60 is opened and the shorting switch 66 is closed. Theshorting switch 66 provides a relatively low resistance path to groundfor the transfer currents that flow during subsequent shiftingoperations of the device. Any suitable electronic switch device, suchVas a transistor, may be used instead of the single-pole shorting switch66. For example, by biasing a junction transistor in known fashion, itscollector-to-emitter path can be made to appear as a relatively lowresistance, in the order of a few ohms, or as a relatively yhighresistance in the order of a megohm or more. The single-throw switch 67is released to connect the condenser 29 to the first output device 33.

The condensers can be reset to their P states by throwing the thirdreversing switch 60 to the right (as viewed in the drawing) to connectthe negative terminal of the reset battery 58 to the common bus 56. Theterminals a of the condensers are thereby made positive relative totheir terminals b, and each condenser is reset to its P state. Recallthat the condensers are reset to their P states when the shiftingoperation is carried out in the reverse direction, from right-to-left.The current-limiting resistor 61 also serves to limit the amount ofreset current owing in the transfer loops when the condensers are resetto their P' states. The transfer currents are each in a direction todrive the cores from remanence in the state N to saturation in the stateN. Thus, after the condensers are reset to their states P', the cores 10all return to, or very near, their initial remanent conditions in thestate N.

The system of Fig. 6 provides another means for resetting the condensersto desired remanent states. Each of the transfer loops 20, 21 and 22 isconnected to the movable arm of a different one of four `single-pole,Vdouble-throw switces 70', 71, 72 andv 73. The center terminal of eachof these switches 70, 71, 72 and 73 is connected to ground. One fixedterminal 70a,.71a`, 72a and 73a. (that on the left)V of each-jof theseswitches is connected'to a rst bus 74'. The other' fixed terminaly 70b,`71b, 72b'and`73b (that on the right) of each of these switches isconnected to a second bus 76,. Theiirstbus 74 is connected through a rstcurrent-limitingI resistor 78to the positive terminal of' afirst resetsource, such asa battery 80.2 The second [bus 76 is connected through aysecond current-limiting resistor 82 to a negative terminal of a secondreset source, such-as a battery 84. The negative terminal of thebattery-80Y and the 'positive terminal of thebattery 84 are connectedto, ground. Ac-` cordingly, by connecting the V'movable farms of theswitches 70, "71, 72 and 73 -to eitherthe left or to the right xedterminals, as desired, the condensers 24,25, 26 and 29 jc anb eY resetto either the KN or the .'P states. After lthe condensers are resetto`desired states, the movable arms of the'switches 70, 71, ',72 and 73arereturnedtotheir center groundedterrninals'. lA systemarranged as isthe system of Fig..6 is useful in certain applications where it isdesired to change the length of the register at diierent times. Forexample,

4 the windings,

lits-initial remanent state P, no transfer current -tlows in thetransfer loop 22 because the condenser 26 already is polarized in the Pstate.

An additional group of auxiliary cores 90, 91, 92 and `93 may be usedfor resetting the condensers to a desired remanent state. In the systemof Fig. 7, each of the transfer loops 20, 21 and 22 includes anadditional aux- .ilia-ry core 90, `91 or 92. The auxiliary core 93 iscoupled between the core 10d and the condenser 29 by way of the lowerset of contacts of the single-pole switch 67. A reset Vline 96. islinked to all the auxiliary cores. A reset source 98 is connected acrossthe reset line 96.

In operation, each of the auxiliary cores is magnetized in an initialstate, for example, the state N. When a signal' is shifted. from onemain core, for example, core 10b, to a succeeding main core, as 10c, theresultant transfer current is in a direction to drive the coupledauxiliary core 9 1. further into saturation in the state N. Accordingly,an auxiliary core merely presents a small, additional resistance in thecoupled transfer loop when a signal is shifted from one main core toanother. After the signal is shifted through all the main cores of thedevice, the main cores are all magnetized in their initial remanentstates, for example, the state P, and all the condensers are magnetizedin one state, for example, the state P. In resetting the condensers, thereset source 98 first applies a positive reset pulse 100 to the resetline 96. The positive reset pulse 100 changes each of the auxiliarycores from its initial remanent state N to the other state P. The fluxchanges in the auxiliary cores each induce a voltage in its coupledtransfer loop in a direction to drive the connected condenser fromremanence in the state P to saturation in the same state P. Accordingly,relatively little current ows in any of the transfer loops when thevauxiliary cores are changed to the state P. After the positive resetpulse 100 is terminated, the reset source 9S applies a negative.polarity reset pulse 102 to the reset line 96. The negative reset pulse102 changes each of the 'auxiliary cores from'the state P to the stateN. The flux changes in the auxiliary cores each induces a voltage in theconnected transfer loop in a direction` to change the condenser of thatloop from the state P' to. the state N. Thus, these induced voltagesnare eachl positive at the electrode b relative to the electrode a ofany ofthe condensers. The resultant current liowin ,the transfer loops,in returning the condensers to the state N', flows into the markedterminals of any of output orinput, of the main cores. Accordingly,thetransfer loop currents `drive each of `the main-2cores from remanence`in the initial state P` to saturation in the` same state P. Upontermination ofthe negative reset pulse 102, all theauxiliary coresv aremagnet'ized in the'state N, all the main cores are magnetizedinfthewstate Rand all ythe condensers are polarized in the state N.

Note-that the system can .be changed toits reset condition at any Vti1ne:,{even Abefore an inputsignall is shifted v to anoutput device, Ifa main core 10 is magnetized .in the state N during the resetoperation,thel auxiliary cores, in changing from the state N to the state'P,change allthe main cores succeeding the one mainv core l0 from'theirinitial states P totheir other states N, and change allthe-,condensers succeeding' the one corefrom their initial states kN Qtoltheir other states VP.

ceding the one main core 10 vThe one A,main core 10, remains in thestate- N andthe-mainzcores 10 pre'.-4 v x remainin the state P. The.;condensers preceding theA one main core 10 remain in' 5. A'system asclaimed in claim condensers that are in the state P' are changed to thestate N'.

There have been described herein-improved systems of the shift-registertype having a plurality of cores of .substantiallyrectangular'hysteresis loop material interconnected by a plurality oftransfer loops each including a different ferroelectric condenser. Notethat the transfer loops receive only induced voltages from the corewindings during the shifting operation. Information is shifted from coreto core by means of a pair of Shift lines each linking alternate ones ofthe cores. Information may be shifted in either direction by applyingeither polarity signal to the shift lines.

What is claimed is: p

1. A system comprising a plurality of cores of substantially rectangularhysteresis loop material, input and output windings on each of saidcores, a plurality of transfer loops connecting said cores byrespectively connecting successive output and input windings ofsucceeding said cores, said'transfer loops receiving only inducedvoltages from said core windings, a plurality of ferroelectriccondensers having two terminals, each of said condensers having arectangular hysteresis loop charactersistic and each of said condensersbeing connected ina different one of said transfer loops by directlyconnecting one of said terminals to the input windings of the loop inthe other of said terminal to the output windings of the loop, a firstshift line linking alternate ones of said cores, and a second shift linelinking the other, alternate ones of said cores.

2. A system as claimed in claim l, said cores each having two remanentstates, and including means for establishing one of said cores in adesired one of said remanent states and the remaining ones of said coresin the other of said remanent states.

3. A system as claimed in claim 1, including means for applying signalsof either one polarity or the other polarity to said shift lines. Y

4. A system comprising a plurality of main cores of substantiallyrectangular hysteresis loop magnetic material, output and input windingson said cores, a plurality of auxiliary cores of substantiallyrectangular hysteresis loop magnetic material, a plurality oftransferloops connecting said main cores by respectively connecting successiveoutput and input windings of succeeding said main cores, said transferloops receiving only induced yvoltages Vfrom said core windings, aplurality of' ferroelectric condensers of substantially rectangularhysteresis loop .matterial, each said transfer loop linking a differentone of said auxiliary cores and including a different one Vof saidferroelectric condensers. p i i second shift lines I-alternately linkingsaid main cores,

" 6.1 A system as claimed in claim 4, including rst' and second shiftlinesalternately linking said main cores,

' `anda reset line linking said auxiliary cores.

`f7.' system as claimed in claim 4, including first Y second shift iinesalternatelyv linking said lnain cores', vand meansfor applying to saidshift lines 'shift signals of either the one polarity or ofthe oppositepolarityjf St'Arsystema's claimed inclaim 6, including means forapplying to said reset line a resetj'signaljcomprising a 'first pulseiof one polarity followed by a second pulse of the opposite polarity: f l9`: vA signal shifting systemcomprising firstand second cores eachhaving two remanent states, windings on said cores,`a`kcondenser havinga dielectric of-fefnroelectric'lma.- `teri'a'l, said condenser havingtwo remanent'states; means for. ysetting l said cores in different onesfoff their said 4; including" @ist an remanent states and for settingsaid condenser in one of its said Aremanent states, a transfer loopconnecting one vwinding ofsaid rst core,said condenser, and one windingof said second core, means for changing the remanent stateV of one ofsaid'cores, said changed core inducing a signal in said transfer loop,said induced signal changing said condenser and the other of lsaid coresto the other of said remanent states. Y

10; A signal shiftingV device las claimed in claim 9, including a loaddevice connected in said transfer loop.

l1. A signal shifting device as claimed in claim 9, including a loaddevice coupled to one of said cores.

" 12. A shifting system comprising a plurality of cores'of-substantially rectangular lhysteresis loop material,

windings having terminals on said cores, separate transfer loops betweensuccessive pairs of said cores, said transfer loops each connecting oneterminal of one said winding on one said core of a pair to one terminalof said winding on the other core of the same said pair, a plurality offerroelectric condensers of substantially rectangular hysteresis loopmaterial, each of said transfer loops including a different one of saidferroelectric conv densers, ishift means linked to said" cores, separateswitch means connected acrosseach of said ferroelectric condensers forapplying unidirectional voltages of either the one or theiother polarityto said condensers, and means for short-circniting4 said transfer loopsbetween the other terminals of said one windings.

13. A system comprising a plurality of magnetic cores each having tworemanent states, and each being magnetized in an initial one of saidstates, a plurality of ferroelectric condensers each having two remanentstates,

land each being polarized in an initial one of said states, a

plurality of transfer loops each including a different one of saidcondensers and each being coupled between dilferent successive ones ofsaid cores, a first shift line linking alternate ones of said cores forchanging said alternate cores from the other to said initial states, anda second shift line linkngthe other alternate ones of said cores forchanging said other ralternate cores from said other to said initialstate, any one of said cores in changing to said initial state producinga signal in one of said coupled transfer loops to change said onetransfer loop condenser from said initial to said other state and tochange the other core of said one transfer loop from said initial tosaid other'state. v

114. A system comprising a plurality of cores' of suhstantiallyrectangular hysteresis loop material, each said core having two remanentstates, a plurality of transfer loops connecting said cores in cascade,a` first of said transfer loops coupling a 4ii-rst and second of saidcores, a

second of said transfer loops coupling said second and a third of saidcores, and so on, a plurality of ferroelectric condensers, each havingtwo remanent states, and `each ones of said cores, and a second shiftline for receiving second shift signalslinking the other, lalternateones`of said coi-espa shift signal, when applied, being effective to .changethe remanent state of one of said? cores, vsaid one coreproducing asignal inone of Vsaid 'transfer loops linkedfthereto, 'and said inducedsignal changingjhe remanentgstates. of both saidv ferroelectriccondenser and ,the 9ther.saic l core Vof said one transfer. loop.

iff ,*Rjeigrefs'cifga in the me df this parent l UNITED STATES PATENTS

